Hardy molecule makes memory

January 14/21, 2004

Scientists are continually trying to shrink
the space a bit of information takes up in order to fit more bits per
square inch in storage media. One idea is to use layers of molecules as
bits in hybrid organic/silicon devices. The challenge is finding molecules
that can stand up to the harsh conditions needed to manufacture silicon
and write and rewrite data.

Researchers from the University of California at Riverside and
North Carolina State University have shown that a type of porphyrin molecule
holds up under temperatures as high as 400 degrees Celsius and after being
written to and read from trillions of times.

The researchers had previously shown that it is possible to use
the molecule to store charge. Charged and uncharged molecules can represent
the 1s and 0s of computer information. The researchers chemically tethered
porphyrin molecules to a silicon platform and used voltage to write charges
to and erase charges from the molecules.

The researchers have also shown that it is possible to store two
or three bits of information per memory element rather than the usual
one. This is significant because it could allow existing 0.13-micron memory
chips to store as much as chips made using future 0.09- or 0.07-micron
manufacturing processes, according to the researchers. The sizes refer
to the smallest elements a chip can contain.

Hybrid semiconductor/organic memory could become practical in
two to five years, according to the researchers. The work appeared in
the November 27, 2003 issue of Science.